U.S. Route 101
U.S. Route 101 or U.S. Highway 101 (US 101) is a major north–south United States Numbered Highway that runs through the states of California, Oregon, and Washington, on the West Coast of the United States. It is also known as El Camino Real (The Royal Road) where its route along the southern and central California coast approximates the old trail which linked the Spanish missions, pueblos, and presidios. It merges at some points with California State Route 1 (CA 1) and Interstate 1 (I-1). Though US 101 remains a major coastal north–south link along the Pacific coast north of San Francisco, it has been replaced in overall importance for transport through the West Coast states by Interstate 5 (I-5), which is more modern in its physical design, goes through more major cities, and has more direct routing due to significantly easier geography over much of the route. US 101 is a major parallel route between Los Angeles and San Francisco, and is an alternative to the Interstate for most of its length. In 1964, California truncated US 101's southern terminus in Los Angeles, as I-5 replaced it, paralleling the Pacific Ocean. The old road is known as County Route S21 (CR S21) or Historic Route 101 in northern San Diego County. The nearly 1,550-mile-long (2,500 km) highway's northern terminus is at I-5 in Tumwater, Washington: the route remains along the Olympic Peninsula's coastal perimeter west, north, south, and east; the northernmost point on the highway is in Port Angeles. The southern terminus of US 101 is at I-5 / I-10 / CA 60 in Los Angeles at the East Los Angeles Interchange, the world's busiest freeway interchange. Numbering According to the American Association of State Highway and Transportation Officials's (AASHTO) numbering scheme for United States Numbered Highways, three-digit route numbers are generally subsidiaries of two-digit routes. However, the principal north–south routes were assigned numbers ending in 1. Rather than number the west coast highway US 91, and lose four available north–south numbers (93, 95, 97, and 99) which, under the numbering plan, are supposed to be west of US 91, or assign the primary west coast highway a "lesser" number (one not ending in 1), AASHTO made an exception to its two-digit rule. Thus, US 101 is treated as a main primary, two-digit route with a "first digit" of 10, rather than a spur of US 1, which is located along the east coast, on the opposite side of the United States. Thus, US 101, not US 99, is the westernmost north-south route in the U.S. Highway System. If US 101 had an auxiliary route, it would probably be a four-digit numbered route, for example: U.S. Route 1101 or 2101. Route description California , looking north, carries Interstate 1, as well as California State Route 1 and U.S. Route 101 from San Francisco to Golden Gate City.]] Oregon Washington Category:U.S. Route 101 Category:United States Numbered Highways Category:Highways and roads Category:Major U.S. Highways Category:U.S. Highways in California Category:U.S. Highways in Oregon Category:U.S. Highways in Washington Category:United States Numbered Highway System Category:Highways numbered 101